Feeding mechanism for automatic firearms



Feb. 8, 1955 w. A. SCHAICH 2,701,564

FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original Filed Nov. 10, 1948 2 Sheets-Sheet l a s wcmfov' Wilh ur A .5 01111-1. c 11.

Feb. 8, 1955 w. A. SCHAICH $301,594

FEEDING MECHANISM FOR AUTOMATIC FIREARMS Original Filed Nov. 10, 1948 2 Sheets-Sheet 2 F 8 Inn" y 42 42 40 1 a9 46 44 45 44 .27 1 ;L i/ 34- E 3.3 a! E 28 v wcmfm Wilbur A- Elc huu'. Eh. I

FEEDING MECHANISM FOR AUTOMATIC FIREARMS Wilbur A. Schaich, Franklin, lVIich.

Driginal application November 10, 1948, Serial No. 59,324. Divided and this application January 17, 1951, Serial No. 206,411

3 Claims. (Cl. 8933) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to a feeding mechanism for an automatic firearm, more particularly to a feeding mechanism for an automatic firearm having a forwardly moving barrel.

This application is a division of my copending application for Firing Mechanism for Automatic Firearm, Serial No. 59,324 filed November 10, 1948 and now issued as Patent No. 2,557,144.

In feeding a cartridge into the chamber of the barrel the bolt of conventional firearms simply scoops off the top cartidge from the magazine, which incidentally is generally fed upwardly in the magazine by a springpressed follower, and seats such cartridge in the chamber. When the last cartridge has been fired, a portion of the follower jumps into the path of the bolt to hold such bolt in the open position. Extraction and ejection of the fired case are handled in a well-known manner. Thus, most recent prior art firearms utilize proven and established principles which greatly simplify the design thereof.

In a firearm having a forwardly movable barrel, however, there are several distinctly different departures from conventional design that require a new approach to the solution. Foremost thereof is the problem of providing a feeding means that can be readily used in a firearm of this type. Inasmuch as there is no reciprocating bolt, the forwardly movable barrel must be utilized for such pur pose. In contrast to conventional firearms wherein the bolt is driven rearwardly after discharge of the firearm, the barrel of the firearm of this invention is driven forwardly. Suitable springs are provided to return the barrel rearwardly to the closed battery position at the completion of the first movement. fore, a substantially difierent construction of the feeding mechanism and related elements.

In the course of further development of this invention other novel and unique features were incorporated which relate to ejection of the fired case, feeding of the cartridge and to an improved magazine construction used in combination with other of the above elements. All of these other features being especially adaptable to a firearm having a forwardly movable barrel may, of course, be utilized with firearms of more conventional construction with but little adaptation.

Accordingly, it is an object of this invention to provide an improved feeding mechanism for an automatic fire-- arm having a forwardly moving barrel, such mechanism being constructed to receive feeding energy from the movement of the barrel.

Another object of this invention is to provide a pair of cocking rods for an automatic firearm to retain the cartridges in the magazine of the firearm while permitting release of a cartridge therefrom in timed relation with respect to the recoiling barrel.

A particular object of this invention is to provide a feeding mechanism for an automatic firearm having a forwardly movable barrel of the type more fully described in my copending application, Serial No. 621,647, filed October 10, 1945 and now matured into Patent No. 2,628,536 dated February 17, 1953.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

This necessitated, therehired States Patent Fig. l is a fragmentary view of a firearm embodying this invention shown in longitudinal section;

Fig. 2 is a detail top view showing the manner in which the cocking rods retain a cartridge in the magazine of the firearm;

Fig. 3 is a detail perspective view of the hammer;

Fig. 4 is a detail view of the ejector;

Fig. 5 is an enlarged detail perspective view of the breech block shown secured to the magazine guard and showing the relationship of the firing pin, cocking rods and ejector;

Fig. 6 is a front view of the breech block showing the arrangement of the various elements on the face thereof;

Fig. 7 is a fragmentary side view of the magazine shown partly in section;

Fig. 8 is a sectional view taken substantially along the line 8--8 of Fig. 7;

Fig. 9 is a detailed view showing the spring seat and stock bolt arrangement;

Fig. 10 is an enlarged detail view of the cartridge locator shown partly in section; and

Fig. 11 is a fragmentary view showing the cartridge locator mounted on the firearm.

There is shown in Fig. 1 an automatic firearm embodying this invention. Such firearm includes a tubular receiver 10 having a threaded rear end (not shown) for securing the receiver to a substantially cylindrical breech block 15. A forwardly facing cup-shaped recess 13 having threads 14 therein is provided to accommodate the threaded end of receiver 10. A threaded portion 16 is provided about block adjacent the rearwardly facing end of such block by means of which a stock support tube 17 is secured thereto.

A magazine support 18 (Figs. 5 and 6) surrounds receiver 10 and breech block 15 and is secured to such breech block preferably by welding. A magazine 20 is readily inserted into magazine support 13 through an opening 21 provided therein for such purpose. A magazine latch 22 pivots on a transverse pin 23 and secures such magazine in magazine support 18. A cartridge ejection port 24 is provided on top of receiver 10 as shown in Fig. l. A barrel 25 is slidably mounted within tubular receiver 10 and such barrel has a chamber 26 to accommodate a cartridge 27. Barrel 25 also has a rear wardly projecting ramp 12 as shown in Fig. 11. An operating sleeve (not shown) is slidably mounted on receiver 10 and extends rearwardly to magazine support 18. Such sleeve is provided to actuate the barrel locking member (not shown) for looking or unlocking the barrel with respect to the receiver. The magazine 20 is preferably a double column, box type having a follower 28 (Figs. 7 and 8) reciprocating therein under the bias of a primary follower spring 29. One side wall 30 of the magazine is of substantially planar configuration while the other wall 31 is bent inwardly near the top thereof to form a single column exit passage 32 for cartridges stored within the magazine.

The follower 28 is formed in two parts comprising a primary follower 33 of suitable width to freely reciprocate within the double column portion of magazine 20 and a secondary follower 34 which is of reduced width permitting it to reciprocate through the top single column portion of the magazine. A secondary follower spring 35 operates between primary follower 33 and secondary follower 34.

The magazine has a desirable feature of having no retaining lips, the cartridge feeding passage 36 being defined by substantially straight vertical wall sections. Because of this arrangement, it is necessary to provide a cartridge retaining latch 37. The latch 37 is pivotally secured to the inwardly bent wall 31 of the magazine by means of a pin 38. The pin in turn is supported between two outwardly projecting ears 39 which are integrally punched out of a reinforcing band 40 which surrounds the top perimeter of magazine 20 and is suitably secured thereto, as by welding. The cartridge retaining latch 37 comprises an inverted, substantially L-shaped member. A short arm 41 of such member projects across the top of magazine 20 in its normal position and thus retains the cartridges within the magazine when the magazine is handled outside of the gun. A long arm 42 of retaining latch 37 extends downwardly along the side wall 31 of the magazine and is shaped to define a hollow bearing portion 43 by which the latch is mounted on the pin 38. Downwardly from the bearing portion 43 are provided integral outwardly projecting cam portions 44 which cooperate with the wall of the magazine support to move the cartridge retaining latch 37 to an inoperative position when magazine is inserted into the gun. The bottom portion of retaining latch 37 is provided with a slot 45 and a torsion spring 46 is mounted in such slot, surrounding the pin 38 and operating between the side wall 31 of the magazine and the long arm 42 of the retaining latch to pivotally bias the retaining latch in such direction that the short arm 41 thereof will project inside the magazine 20 and thus retain the cartridges therein.

The walls of the central portion of magazine support 18 are shaped to substantially conform to the shape of the top portion of magazine 20. Such central portion is bulged outwardly to provide clearance for the magazine retaining latch 37 when the magazine is assembled to the gun.

As the loaded magazine is pushed upwardly into the magazine recess of the magazine support, the bottom edge of such support engages the cam portion 44 of cartridge retaining latch and pivots such latch clockwise thereby moving the short arm 41 to a position outside of the path of the stack of cartridges and permitting the entire stack of cartridges to rise upwardly under the bias of spring pressed follower 28. Since the magazine has no retaining lips, and if the barrel is in its forward position exposing the magazine exit 32, the entire column of cartridges would be fed upwardly into the receiver 10 and obviously produce a jam. To prevent such occurrence. a cartridge locator 115 is provided to act as a stop for the vertical movement of the top cartridge in the ma azine stack, permitting such cartridge to rise only sutficiently high within receiver 10 that the nose thereof may be engaged by the ramp 12 of barrel 25.

Cartridge locator 115 is pivotally mounted between ears 116 of the magazine support on a transverse pin 171. A relatively long rearwardly projecting portion 118 of the cartridge locator 115 is suitably shaped to engage the large diameter portion of the top cartridge in magazine 20 when the barrel is in its forward position. The cartridge locator 115 is pivoted to its proper position with respect to the top cartridge by the cooperation of a cam surface 119 on the bottom of cartridge locator 115 which extends forwardly past pin 171 with a cam groove 120 which extends longitudinally along the top of barrel 25. Cam groove 12!) is shaped to pivot the cartridge locator in a counterclockwise direction as the barrel moves forwardly and to hold the end portion 118 of the cartridge locator at a fixed distance above the top of magazine exit 32 when the barrel is in its extreme forward position. Thus the top cartridge of the magazine stack will be properly positioned to be picked up by the barrel ramp 12. This feeding mechanism obviously increases the reliability of feeding inasmuch as magazine lips are entirely eliminated and the cartridge is free to ride into the chamber.

If at any time it is desired to remove magazine 20 from the gun while there are still some cartridges remaining therein, such may be accomplished without loss of the remaining cartridges in the magazine. As the magazine is pulled downwardly out of the magazine support, the cam portion 44 of the retaining latch 37 moves out of engagement with the magazine support and accordingly, the retaining latch 37 pivots in a counterclockwise direction as viewed in Fig. 8 under the bias of torsion spring 46 and short arm 41 of the latch moves across the magazine exit 32 to retain the remaining cartridges therein.

It is generally desired that a magazine fed firearm for military use include a device for locking the action in the open position after the firing of the last round from the magazine. This may be readily accomplished in a firearm embodying this invention. A pair of spaced. transversely extending lugs 124 (Fig. 10) are integrally formed on a forward cylindrical portion 125 of magazine support 18. A last round barrel step 126 is mounted on a rod 127 which is supported by lugs 124. Barrel stop 126 is mounted rearwardly of the rear lug 124 and is rigidly secured to rod 127 so that rotatable movement of rod 127 will in turn rotate the stop 126 through car- Cal tridge ejection port 24 in receiver 10 into the path of the barrel when the barrel is in its extreme forward position. To reduce the shock caused by the impact between the rear end of barrel 25 and barrel stop 126, rod 127 has an enlarged shoulder 128 formed thereon, and a suitable buffer spring 129 is mounted around rod 127 operating between the shoulder 128 and the forward face of the rear lug 124. The rod 127 is provided with a squared forward end portion 131 on the forward end of which is fixedly mounted an actuator 13% having a rodlike extension 132 which projects into engagement with a cam slot 133 provided in the forward portion of cartridge locator 115. A light torsion spring 134 is provided to bias cartridge locator in a counterclockwise direction. The bias of spring 134, however, is sufficiently light so as to be readily overcome by the magazine follower spring 29 when it is urging a cartridge upwardly against the cartridge locator 115. When, however, the last round has been fired from the magazine, the bias of spring 134 rotates cartridge locator 115 an additional amount until the rear end 118 of the cartridge locator contacts the top of the magazine. This additional rotation of cartridge locator 115 is transmitted through the action of cam slot 133 on actuator to rotate the barrel stop 126 into the path of the barrel when the barrel is in its extreme forward position. As the barrel re turns from its forward position under the bias of an operating spring (not shown), it strikes barrel step 126. The impact forces, however, are absorbed by compression of buffer spring 129.

A pair of oppositely spaced, longitudinal holes 47 and 48 (Fig. 6) are provided through breech block 15 to accommodate .two cocking rods 49 which will be described in more detail later. The right-hand hole 48, as viewed in Fig. 6, is of larger diameter to accommodate in addition a sleeve-like ejector 50. The diameter of ejector 50 is selected so that a portion of the periphery of its forward end will pass through a cartridge seating recess 51 provided in the face of breech block 15 and thus ejector 50 will engage the base of any cartridge seated in such recess. The extreme rear portion of e ector 50 (Figs. 4 and 5) is provided with a radially extending flange 52 which is disposed behind and cooperates with a flange 53 on a firing pin 54 to retain firing pin 54 within a firing pin recess 55 against the bias of a firing pin spring 56. The ejector 50 is in turn retained within breech block 15 by means of a suitable transverse pin (not shown) which cooperates with a longitudinally extending, flat surface 57 (Fig. 4) on the ejector, thereby permitting only limited longitudinal movement of the ejector with respect to the breech block. The length of the ejector is carefully proportioned with respect to the length of the firing pin in a manner that will be more fully described later. A radial extractor recess 58 (Fig. 6) is provided in the face of breech block 15 to receive an extractor 59.

The mechanism of this invention is built around cocking rods 49. These rods are threadably secured to the barrel at their forward ends, and, in all positions of the barrel, the rods extend rearwardly respectively through the cocking rod holes 47 and 48 in the breech block 15 and the bore of the sleeve-like ejector 50, which is slidably mounted in hole 48 in the breech block.

The hammer mechanism for a firearm utilizing a forwardly moving barrel is substantially different from that of a conventional firearm. In the conventional firearm, the hammer is cocked by being over-ridden by the bolt in its rearward movement. In a firearm constructed in accordance with this invention, the only major moving element is the barrel and that is moving away from the rear of the breech block which is the necessary location of the hammer mechanism.

A hammer 60 (Figs. 1 and 3) is slidably mounted on the cocking rods 49 rearwardly of breech block 15. The hammer 60 is provided with two parallel, spaced, longitudinally extending, horizontal holes 61 in which the cocking rods are engaged. A transverse slot 62 is cut across the top of hammer 60, extending into both of the holes 61. A generally rectangular, spring biased, sear 63 is mounted for vertical movement in the slot 62 and in its lowest position, projects into horizontal holes 61.

An annular sear notch 84 (Fig. 2) is provided in each of the cocking rods 49. These notches are shaped to permit the sear 63 to drop therein and thus in the battery position of the barrel secure the hammer against forward movement relative to the cocking rods by engagement of the front wall of the sear 63 with a rearwardly facing shoulder 85 defined by the sear notch 84. A rear wall 86 of scar notch 84 is tapered so as to permit sear 63 to be cammed upwardly upon occurrence of forward movement of the cocking rod relative to the hammer. The bottom surface of sear 63 may be similarly angularly inclined to facilitate such camming action.

operating spring 88 (Fig. l) is mounted in surrounding relation on each of the cocking rods 49 and operates between a spring seat 111 (Fig. 9), connected to the rear end of the cocking rods, and the rearwardly facing wall of hammer 60. Spring seat 111 comprises a cup-shaped member, having the opening therein disposed to the rear, and having two spaced holes 112 through the base portion thereof to accommodate the cocking rods 49. A transverse pin 113 is passed through suitable aligned holes in the extreme end of the cocking rods 49 and this pin secures spring seat 111 to cocking rods 49 against the bias of operating springs 88.

The over-all length of firing pin 54 is carefully proportioned with respect to the over-all length of ejector 50. This proportioning also takes into consideration the longitudinal location of the projecting flange 53 on the firing pin. The arrangement is such that when the ejector is in its battery position, i. e., with the cartridge 27 forcing its forward end flush with the base with cartridge seating recess 51, the rear end of the firing pin projects beyond the rear end of the ejector for at least a tenth of an inch. The firing pin is of course pushed rearwardly to such position by the firing pin spring 56 and is retained in such position by the cooperation of the ejector flange 52 with the firing pin flange 53. Thus, in the battery position of the firearm, when the hammer drives forward it will strike the firing pin first and then come to rest against the ejector. The firing pin drives forward by inertia to fire the cartridge. As the action (not shown) is unlocked and the barrel moved forwardly by the operation of the gases, the cocking rods 49 are likewise moved forwardly, pulling the spring seat 111 forwardly, thereby compressing operating springs 88 against the rear face of the hammer and thus producing a steadily increasing, forwardly directed spring force on the ejector 50. When the rear end of the barrel moves forward sufficiently to clear the forward end of the cartridge case, which, of course, is retained in cartridge seating recess 51 by the extractor 59, the ejector will move forward and flip the cartridge sharply out of the receiver 10.

It should be noted that this ejector arrangement has three very desirable features; first, it requires no separate spring which is in distinct contrast to the conventional spring pressed ejector; secondly, it has available substantially the full force of the compressed operating spring to produce ejection, which thus imparts a very strong ejecting force to the base of the cartridge; finally, it does not require compression of any spring as the cartridge is being seated in battery position, hence reducing the amount of energy required to move the barrel into battery position and facilitating operation of the locking mechanism.

The forward movement of the ejector after ejecting the fired cartridge is limited by engagement of a portion of its front periphery with the rear end of the receiver 10. By cutting back that portion of the ejector which would strike the rear end of receiver as indicated at 89 (Figs. 4 and 6) the stroke of the ejector may be made as long as desired, which again is in distinct contrast to conventional spring pressed ejectors which all have the disadvantage of having a very limited stroke, due to the necessary design characteristics of the conventional ejector spring.

The length of the ejector is proportioned to the over-all length of the firing pin so that in the extreme forward position of the ejector, the longitudinal distance from the front face of the hammer to the base of the cartridge seating recess 51 will be slightly greater than the over-all length of the firing pin, thus assuring that at no time after the initial firing pin blow will the point of the firing pin protrude into the cartridge seating recess 51. This feature, of course, insures that no fresh cartridge will be accidentally fired as it is initially moved by the barrel into its battery position.

When the barrel returns to the battery position, the cooking rods 49 are of course moved rearwardly with the barrel and when the sear notches 84 of the cocking rods pass beneath the sear 63, they are engaged thereby, whereupon the hammer is moved rearwardly by the cocking rods to its battery position maintaining operating springs 88 in a compressed condition. The inertia of the barrel insures that it will return to battery position. The spring seat 111 is constructed to strike a stock bolt 19 (Fig. 9) before the cooking rods reach their extreme rearward position. By this action, any further rearward movement of the barrel into battery position produces an additional compression of the operating springs 88 and thus the operating springs perform the additional function of cushioning the movement of the barrel as it comes into battery position, thus eliminating a rearward jar which would otherwise be transmitted to the operators shoulder.

Cocking rods 49 may be modified in such fashion that such rods may be utilized to retain the cartridges in magazine 20 thereby eliminating the cartridge locator 115. When the barrel is moved forwardly to its open position, the cartridges in the magazine tend to rise upwardly under the bias of the follower spring, but the top cartridge 27 of the stack is retained in proper position to be picked up by the ramp 12 of barrel 25 through the cooperation of the opposed interior edges of the cocking rods 49. The cocking rods in this modification are each provided at their forward ends with a flat surface (Fig. 2) which in assembled relationship are vertically and oppositely disposed. These fiat surfaces 110 may conveniently extend from the forward end of the cocking rod rearwardly to the sear notch 84. At any event, the distance between such surfaces is proportioned so as to permit cartridge 27 to pass freely thercthrough in a vertical direction. The remaining portion of the cocking rods 49, however, is of such diameter that the space between such rods will not permit a substantial portion of the rear, large diameter end of cartridge 27 to pass upwardly therebetween as illustrated in Fig. 2.

Thus, as the barrel moves forwardly and clears the nose of the top cartridge, the cartridge then rises somewhat, but the extent of its vertical movement is limited by the engagement of the rear portion of the cartridge with the large diameter portions of the cocking rods to the rear of the sear notches 84. In this position, however, the top cartridge is sufficiently elevated so that its nose is in position to be picked up by ramp 12 of barrel 25. Thus, as the barrel returns to battery position, it scoops up the nose of the next cartridge and due to the smaller diameter of the forward end of the cartridge, a substantial portion of the cartridge can enter the chamber at an angle irrespective of the fact that the rear portion of the cartridge is held down by the cocking rods. When the barrel has moved approximately an inch rearwardly toward its battery position, the large diameter portions of the cocking rods pass off the end or" the cartridge and the cartridge is free to move upwardly between flat surfaces 110 and into the barrel by the relative movement of the barrel with respect to it. At the same time, however, the next cartridge is maintained in a depressed position because of the fact that the bottom of the barrel is overlying the forward part of such cartridge.

From the foregoing description it will, therefore, be apparent to those skilled in the art that there is herein disclosed a novel construction and improvement which are adaptable to firearms of conventional actions as well as firearms embodying a forwardly moving barrel. The ejector arrangement is unique in that no separate spring is required to produce ejection, utilization of the driving spring being made for such purpose. Lastly, the magazine construction is of simple design and positive operation, being suited for use in any firearm adapted to receive a box magazine. Such magazine is, however, particularly effective when employed with the cartridge locator herein described.

I claim:

1. In a firearm having a receiver, a box-type magazine removably secured in the receiver and arranged to contain a stack of cartridges therein, and a barrel slidably mounted in the receiver for reciprocal movement forwardly from and rearwardly to a battery position, the combination of a cartridge-locating member pivotally mounted in the firearm above the path of barrel movement and having a downwardly and rearwardly projecting arm terminating in a cartridge-engaging portion, cam means in the top of the barrel engageable with the underside of said cartridge-locating member as the barrel concludes the forward movement thereof whereby said cartridge-locating member is pivoted so that said cartridge-engaging portion thereof depresses the stack of cartridges in the magazine and thereby aligns the uppermost cartridge in position to be chambered during rearward battery movement of the barrel, resilient means continually biasing said cartridge-locating member in the direction of pivotal movement imparted thereto by said cam means in the barrel whereby said projecting arm is advanced an additional amount in the absence of cartridges in the magazine until said cartridgeengaging portion thereon contacts the top of the magazine, said cartridge-locating member having a cam slot in the foward end thereof, and barrel stop means rotatably mounted to the side of the receiver, said means including an actuating arm fixedly secured thereto and engageable in said cam slot whereby said additional movement of said cartridge-locating member rotates said actuating arm to position said stop means in the path of rearward movement of the barrel for holding the barrel out of battery position and thereby indicating the absence of cartridges in the magazine.

2. In a firearm having a box-type magazine for receiving an upwardly biased stack of cartridges therein, a barrel slidably mounted for longitudinal movement forwardly from and rearwardly to a battery position, a cartridge-locating member pivotally mounted in the firearm above the barrel, cam means in the top of the barrel engageable with the underside of said cartridgelocating member for imparting pivotal movement thereto during the conclusion of forward movement of the barrel whereby said member is actuated to depress the stack of cartridges for positioning the uppermost thereof 3 in chambering alignment with the barrel, spring means biasing said cartridge-locating member in the direction of pivotal movement imparted thereto by said cam means in the barrel whereby the absence of cartridges in the magazine permits said cartridge-locating member to pivot into contact with the top of the magazine, a pair of spaced-apart mounting lugs fixedly secured to the side of the firearm adjacent said cartridge-locating member, a rod-like member rotatably mounted in said lugs, said rod-like member having a depending arm fixedly secured to the rear end thereof and an actuating arm fixedly mounted to the front end thereof, said cartridge-locating member having a cam slot in the forward end thereof for receiving the end of said actuating arm therein whereby the additional pivotal movement imparted to said cartridge-locating member by said spring means rotates said actuating arm to thereby rotate said rod-like member and bring said depending arm into position to stop the barrel out of battery position and thereby indicate the absence of cartridges in the magazine.

3. The combination defined in claim 2 including a collar fixedly secured on said rod-like member between said mounting lugs, said depending arm on said rodlike member being disposed rearwardly of said rear mounting lug and said actuating arm being disposed rearwardly of said front mounting lug, said cam slot in said cartridge-locating member being of reverse L- shaped construction whereby said rod-like member is free to move rearwardly upon impact between the rear end of said barrel and said depending arm, and a coil spring surrounding said rod-like member in abutting relation with said front mounting lug and said collar whereby said spring cushions the impact between the barrel and said depending arm.

References Cited in the file of this patent UNITED STATES PATENTS 663,955 Burgess Dec, 18, 1900 663,956 Burgess Dec. 18, 1900 715,971 Burgess Dec. 16, 1902 2,053,489 Norman Sept. 8, 1936 

